Manufacture of lubricating-grease.



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aoiann'r nonsense, or 'rnorsnonr, GERMANY.

MANUFAGTUBE OF LUBRICAX'ING-G-REASE.

No Drawing.

To all whom it may concern Be it known that I,-Dr. ROBERT HfiLs- BERG, manufacturer, a subject of the Emperor of Germany, residing at Troisdorf,

Rhine Province, Germany, have invented certain new and useful Improvements in the Manufacture of Lubricating-Grease, of which the following is a specification.

Before the introduction of mineral oils for lubricating engines and the like, oils directly furnished by processes of nature were commonly used, such as olive oil, colza oil, and linseed oil; also certain animal oils, such as tallow and other fats were employed. When, however, petroleum came into promie nence the by-products obtained in the course of its treatment, especially the mineral lubricating oils, in time to a great extent supplanted the more expensive animal and vegetable oils.

The consumption of mineral oils at the present time is very considerable as is well known, and just as mineral oil has supplanted vegetable and animal oils, so has the consistent engine grease produced from mineral oils taken the place of greases obtained from vegetable and animal oils. Lu-

brication with engine grease has in several respects advantages over the use of mineral oils, namely, as regards economy of lubricant, cleanliness and convenience. These advantages, however, are in most cases not equivalent to those associated with oil lubrication, since the best of known lubricating greases are inferior in lubricating properties to the lighter mineral oils. Moreover, engine greases, as hithertoemployed, consume a considerable amount of power by reason of their internal friction, so that their use is in this respect uneconomical,

especially for lubricating parts running at high speeds and under heavy pressure, The

rapid wear of the sliding surfaces off the one hand, and the loss of power on the other hand, are both factors which forbid the use of grease where high efliciency is aimed at.

The comparatively poor quality of the lubricating grease on the market at the present time is due largely to the method of manufacturing it. One method of manufacture consists in dissolving lime soap in mineral oil and stirring this solution with a small quantity of water added thereto in ordinary open boilers, vessels, or in apparatus specially constructed for this purpose, consisting of open boilers and stirring Specification of Letters Batent.

mama oct. 10, rare.

Application filed November 12, 1913. Serial No. 800,678.

tion ofthe greasy substance under treat-- ment, and consequently loss of material, and the operatives are liable to be seriously scalded. Owing to the considerable quantity of froth formed, slow and very careful boiling is necessary until the water content has been reduced to a certain proportion by evaporation. When the requirements for obtaining a uniformly combined grease have been met, and the saponification' and general binding of the grease have been completed, the product which is still liquid is pumped into a boiler and stirred therein, until a uniform grease is obtained, when cold. In this grease the lime soap is in the form of a colloidal solution, and the water is finely distributed in the grease, so that the mass forms an emulsion. Lubricating grease produced in this manner contains a comparatively large quantity of unsaponified particles of lime, which, in conjunction with the lime imperfectly combined with the oil and fat acids, results in the above mentioned disadvantages. i

The object of the present invention is to produce a consistent lubricating grease, which is not only free from the objectionable features above mentioned, but is even superior, as regards lubricating. qualities, to

the ordinary mineral lubricating oils. This object is attained according to the invention by heating the materials used for the production of the grease, such as mineral oil, olein, lime and the like, under a pressure higher than atmospheric pressure, the heating being carried to a suitable temperature, which is then maintained. Particularly suitable substances are oil and fatty acid compounds of the earth alkalis, for instance hydrate of lime (lime milk), and similar compounds of magnesium and aluminium, the acids for example olein, stearin, and palmitic acid and the like, being of animal or vegetable origin, derived from tallow, olive oil, cotton oil and the like, these compounds being mixed with ordinary commercial mineral lubricating oil. The invention is, however, not confined to the specific substances cited.

The process may be carried out with the aid of closed boilers (autoclaves) such as used in the manufacture of soap, and a pressure of about 5 atmospheres and a temperature of 150 C. are employed. This pressure and this temperature have been found to be particularly suitable for carrying the process into efi ect, but it must be understood that the invention is not confined to these particular values. It is possible to obtain good or adequate results'when usingpressures between 1 and 10 atmospheres and temperatures between 110 and 400 C. The heat is preferably supplied by superheated steam of approximately 400 (1., the heating being continuedfor a number of hours, tests being made at intervals until all solid fats have been dissolved. When, after maintaining the temperature and pressure for a suitable period, the substances have united, the contents of the boiler .are left to stand for about 12 hours, whereupon, after the grease and water have become completely separated, the still liquid grease is drawn ofi', poured into pans and allowed to cool.

The improved process has the advantage that a very large quantity of chemically highly combined lime soap in a very finely divided condition is taken up by the mineral oil, the resultant grease obtained in this simple and reliable 'manner is far superior to that obtained accordihg'to the old methods. The following is a specific example ofone of the several Ways of carrying out the present process, but the applicant does not limit himself to the exact quantities or to the particularv materials specified therein: 2500 kg. mineral oil, preferably American, is heat ed to 100 C. with 210- kg. tallow or talgol and 40 kg. stearin from wool fat in autoclave. By talgol is meant a hardened oil.

The autoclave may be provided with a double casing, through which steam is led for heating the mixture; or else by supplying the autoclave on the inside with a steam hose, through which steam also is conducted or else permitted to run out into the contents of the autoclave. In either. case, it is recommendedtouse superheated steam. Inplace of heating by steam, the autoclave may naturally also be heated directly by fire. If the steam is admitted. directly to the contents in the autoclave, the condensed matter as soon as the fat is ready, is separated from the latter, and may be taken away by itself. The heating of the mineral oil, tallow and WOOl stearin is continued until all the solid fats have been dissolved. Thereupon 400 kg. of oleic acid and 260 k of hydrate of lime is pumped into the autoc ave. The entire contents is then kept at a temperature of 150 C. under a pressure of about five atmospheres, until a test of the mass shows that the fat has homogeneous consistency. After standing for several hours, the contents of the autoclave are removed. The fat, when completely cooled, attains a considerable hardness and has, a consistency similar to wax in appearance and with a melting point about 99 In place of 210 kg. tallow and 40 kg. woolstearin, corresponding quantities of vegetableand animal-oils and fats may be used.

In accordance with practical experience, a lubricating grease of similar'quality is obtained by'adding bees-Wax, fin, wool fat olein, palm oil, cotton oil or even cotton stearin. Experience shows moreover, that in place of hydrate of lime, other metal oxids may be used, as for instance, hydrates of magnesium, aluminium or strontium. The quantities of these hydrates depend evidently on their molecular relation.

-Having thus 'described my invention, 1 claim as new, and desire to secure by Letters Patent,

1. The process of producing lubricating grease which consists in mixing oil acid or fatty acid compounds of earth alkalis, with mineral oil and boiling the mixture at a pressure of about 5 atmospheres at a temperature of about 150 C.

2. The process of producing lubricating grease which consists in mixing oil acid or fatty acid compounds of earth alkalis, with mineral oil and boiling the mixture at apressure of about 5 atmospheres at a temperature of about 150 C. by means of superheated steam.

In testimony whereof I affix my signature presence of two witnesses. DR. ROBERT HULSBERG.

Witnesses:

LOUIS VANDORY,

OSCAR DEPNER.

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